The third in a series of Fanny Hill adventures tops them all. Unbeknown to Fanny, she becomes involved with the famous German ace, the Red Baron.

Due to engine trouble, the young German is forced to land his plane behind the British lines. He covers his plane with camouflage netting and after a change of uniforms with a dead soldier, he makes his way to a royal medical hospital and poses as a Belgian. To his joy he finds the hospital made up of a bunch of swinging nurses who are willing to do anything to keep up the patients' morale. Leaving such pleasure to the officers, he helps a German prisoner of war escape with the instructions to have a faulty part of his engine flown back and dropped at dawn at the hospital.

The nurses give a wild can-can party during which the prisoner escapes. While biding his time, the Red Baron enters the festivities.

Fanny Hill's boy friend, a young pilot, is jealous of the German and although he is discharged from the hospital before the party, he continues his investigation to prove the self-styled Belgian, a phony.

As dawn breaks, the boy friend is flying his plane, back to the hospital with a report of his findings. A German plane drops the necessary part for the Red Baron. In the confusion, the Red Baron fixes his plane and gets air-borne to fight the allied officer. Fanny watches with much concern as her loved one's gun jams. It looks like the Red Baron is certain to shoot him down. But true to the Red Baron's code, he breaks away for Germany leaving the young officer no alternative but to land his plane and continue his affair with Fanny.